Many vehicles and other devices include electronic control units (ECUs) that govern a variety of tasks. The ECUs can be programmed to execute computer-readable instructions and control mechanical and/or electrical devices based on those instructions. For example, a powertrain control module (PCM) can act as a central decision making authority for the powertrain of a vehicle and take the form of an ECU to carry out that purpose. A number of vehicle engine parameters can be controlled by the PCM, such as ignition timing of an internal combustion engine (ICE) or an exhaust gas recirculation (EGR) valve to name a few.
The manufacturers of the vehicles or devices may wish to regulate access to the instructions or other operating aspects of the ECUs. Using the example above, a vehicle manufacturer may wish to limit access to the instructions and other features of the ECU to authorized individuals. In the past, access to the ECUs has been granted or denied using a password. However, a large number of ECUs commonly use one password and if the password is discovered for one ECU such a discovery can render all other ECUs using that password unprotected as well.